This invention relates to titrating method and apparatus, and more particularly to an improved titration controlling method and apparatus wherein variations in a titration system are successively detected electrically, and the quantity of each intermittent titre is controlled based on an electric signal thus obtained until an end point of the titration is attained.
Recently, automatic titration apparatus are widely used in various fields of chemical analysis. In typical examples of the titration apparatus, variations in the titration system are electrically detected one after another, and the quantity of each intermittent titration is controlled by the electric signal thus obtained until an end point of the titration is determined from the amount of the titre.
In this type of the titration apparatus, however, the end point control becomes inaccurate depending on the titration curve thereof, so that in worst cases the entire titration cannot be performed satisfactorily. More specifically, where the titration is terminated at the end point, as the sensitivity of titration, that is, the variation in the titration system caused by each intermittent titration ordinarily increases abruptly in the vicinity of the equivalent point, so that in order to have an appropriate titration, the quantity of each titration must be reduced in correspondence to the increase in the sensitivity. However, since the increase in the sensitivity widely varies depending on the substance to be titrated, and for this and other reasons such as a delay in the titration reaction and a delay in the detection of the titration result, it is difficult to find out optimum condition for the titrating operation, rendering inaccurate the end point control of the titration which leads to the failure of the entire titration.
Furthermore, according to the conventional process, a precise detection of the equivalent point has been difficult, and, furthermore, owing to the additional requirements of, for instance, recording, preparation of diagrams, and mathematical calculations, the titration operation has been troublesome and complicated.